Ultrastructure of the early stages of carposporophyte development in the red algaChondria tenuissima (Rhodomelaceae,Ceramiales) |
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Authors: | I Tsekos E Schnepf |
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Institution: | (1) Botanical Institute, University of Thessaloniki, 54006 Thessaloniki, Greece;(2) Zellenlehre, University of Heidelberg, D-6900 Heidelberg, Federal Republic of Germany |
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Abstract: | The ultrastructure of the early stages of carposporophyte development in the marine red algaChondria tenuissima has been studied. The diploid carposporophyte grows on the gametophyte. Apical gonimoblast cells develop into diploid carpospores.
The basal gonimoblast cells cease to divide and undergo considerable cytoplasmic changes before they become incorporated into
the expanding fusion cell. Nucleus and plastids degenerate gradually, while mitochondria remain intact. The smooth endoplasmic
reticulum becomes prominent, it seems to produce small vesicles with electron dense contents. Simultaneously, numerous mucilage
sacs are formed, presumably from dilating ER cisternae. The contents of the mucilage sacs are secreted by exocytosis. The
pit connections between gonimoblast cells flare out. They remain as isolated bodies without connection to a wall after fusion.
Secondary pit connections occur between vegetative gametophyte cells and sterile carposporophyte cells. There are three different
morphological types of pit connections. |
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Keywords: | Algae Rhodophyceae Ceramiales Rhodomelaceae Chondria — Carposporophyte development fusion cell gonimoblast cells pit connections |
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